This invention is directed to a support cushion suitable for seat cushions and mattresses and, more particularly, to a cushion formed of layers of staple polyester fibers blended with sheath/core binder fibers.
Years ago, the stuffing for seat cushions was formed of natural fibers such as cotton or cellulosic based synthetic fibers such as rayon. In more recent years, the furniture industry in the construction of seat cushions and mattresses has moved toward foamed polymeric materials. There are several disadvantages to foamed polymeric materials including the facts that: 1) in case of fire, such foams often generate toxic gases; 2) some of the foams are or can develop characteristics that are irritating to certain allergies; and 3) it is difficult to develop consistent uniformity in the seat support characteristics of cushions made of various types of foam. For the purposes of this disclosure, the term "support cushion" includes both seat cushions and mattresses, i.e., those cushions which support a substantial portion of the human body, whether it be in the seated or reclined position.
There have been some attempts to construct support cushions from staple polymeric fiber. In one approach, staple polymeric (usually polyester) fiber is blown into a cover in the same manner as pillows and an upholstered covering placed therearound. This is not a satisfactory approach to support cushioning, because the support simply is not there. Another approach, as best illustrated in U.S. Pat. No. 4,668,562 to Street, involves the vacuum bonding of non-woven polymeric fibers under compression to densify the fibers to a desired extent. In this construction, fibers of a relatively high melting point and fibers of a relatively low melting point are mixed. When the batt is then heated and placed under compression, the lower melting point fibers melt and bond the other high-melt-point fibers together, holding them together in the compressed state, therein resulting in a denser layer of fibers than would be achieved in a non-compressed state. While this approach offers some advantages, there are certain difficulties attendant thereto. For example, it is difficult to get a soft surface with such approach; it is difficult to simulate a down or other feather construction; it is difficult to obtain a construction that conforms well to the shape of the human body; and difficult to obtain a uniform density in construction.
A more recent patent to Marcus No. 4,818,599 suggests the advantages of blending slickened polyester fiber and binder fiber in which the polyester may be solid or hollow. An older patent to Pamm No. 4,281,042 teaches a 3-component batt including slickened polyester fibers, unslickened polyester fibers, and binder fibers all blended together. None of these references, however, recognize the advantages to be gained of using different combinations of polyester and binding fibers in different layers of a cushion utilizing such varying characteristics as denier and slickening.
In the present invention, first of all, there is an attempt to form an improved fibrous polymeric support cushion by blending polyester fibers, preferably hollow polyester fibers, with sheath/core binder fibers in a non-compressed construction. While the resulting cushioning may be formed as a thick single layer, preferably it is formed as a plurality of layers laminated together. In such a construction, each layer may utilize fibers of different denier and characteristics. As contemplated in the present invention, the polyester fibers should have a denier in the range of 4 to 40.
While conventional polyester fibers may be utilized within the scope of the present invention, more recently there has been developed a hollow fiber configuration which provides significant advantages in cushion crown, bulk support, durability, and reduced weight when compared to conventional fibers of the same denier. Because of their greater bulk and filling power, hollow fibers therefore achieve a more attractive crown and plumpness without an increase in weight. Stated otherwise, hollow fibers provide superior performance at the same weight or the same performance at less weight.
Recently, there has been developed a sheath/core binder fiber (also sometimes referred as a dual-polymer binder fiber) in which a concentric core of one polymeric material (for example, polyester) surrounded by a special low-melt-point polymer sheath which, after exposure to heat, melts and bonds the core fiber with adjacent, more conventional, fibers. This provides cohesiveness and strength to the final product.
In a more specific embodiment of the present invention, the support cushion includes a plurality of layers of staple polymeric batt laminated together, each of the layers including a combination of polyester fibers and sheath/core binder fibers bonded together. In each layer, the polyester fibers make up more than 50% of the batting. In order to custom design a cushion of described characteristics, the denier or other characteristics of the polyester fibers in some layers may vary from the denier and characteristics of the polyester fibers in other layers.
It is, therefore, an object of the present invention to provide an improved support cushion formed of bonded staple polyester fibers.
It is another object of the present invention to provide an improved support cushion of the type described which simulates a down or other type of feather cushion on or adjacent to the surface thereof; however, which cushion includes layers therebeneath which have improved support characteristics.
It is yet another object of the present invention to provide a laminated support cushion which is formed primarily of a plurality of layers of bonded polyester fibers; the polyester fibers for each layer being selected to achieve a resulting cushion which has desired characteristics of surface softness and underlying firm support.